Fendt 1.2.C3 – A051 - ECU, engine control unit (EDC 7): CAN bus B, break in wiring or short circuit

Communication failure on the CAN bus network (EDC control module to injection pump controller). When this fault occurs, the engine typically goes into a restricted operating mode, dropping to an idle speed of 720 rpm, though it may still be possible to drive using the foot throttle/throttle pedal.

• 411 Vario COM III
• 412 Vario COM III
• 413 Vario COM III
• 414 Vario COM III
• 415 Vario COM III
• 712 Vario COM III
• 714 Vario COM III
• 716 Vario COM III
• 718 Vario COM III
• 818 Vario COM III
• 820 Vario COM III
• Fendt 300 Vario COM III
• Fendt 400 Vario COM III
• Fendt 700 Vario COM III
• Fendt 800 Vario COM III
• Fendt 900 Vario COM III (Models 916, 919, 920, 922, 924, 926, 927, 930, 933, 936)

1. 1

   Check the CAN bus B wiring harness for any physical breaks, chafing, or short circuits to ground or battery

2. 2

   Inspect the physical connection between the EDC control module (A051) and the injection pump controller

3. 3

   Consult Fendt wiring diagram 'Sheet 36' (or the 'EDC Control' circuit diagram) to trace the exact pinouts for CAN bus B

4. 4

   Connect the SERDIA (Deutz engine diagnostics program) tool to read the specific internal fault code, which will display as FC:00C1

1. 1

   Power Down

   Turn off the tractor and disconnect the battery to prevent electrical spikes.

2. 2

   Locate the ECU

   Locate the A051 Engine Control Unit. On many Vario models, this is located at the right entrance step, behind the battery case.

3. 3

   Test the Harness

   Disconnect the harness at the ECU and at the injection pump controller. Use a multimeter to perform a continuity test on the CAN High and CAN Low wires for CAN bus B. Test for resistance and ensure there is no short to ground.

4. 4

   Repair Wiring

   If a break or short is found, repair the damaged section of the wiring harness or replace the connector pins if they are corroded or loose.

5. 5

   ECU/Pump Controller Assessment

   If the wiring tests perfectly, the fault lies internally within either the injection pump controller or the EDC 7 ECU itself.

6. 6

   Clear Codes

   After repairing the wiring or replacing the faulty module, reconnect the battery. Connect the SERDIA diagnostic tool and delete error FC:00C1.

7. 7

   Test Drive

   Start the engine and verify that the tractor no longer defaults to a 720 rpm idle and that full throttle control is restored.